In a large mixing bowl, whisk together the flour, milk, eggs, melted butter, sugar, and vanilla extract until smooth. Let the batter rest for 15 minutes.
Heat a non-stick skillet over medium heat. Pour about ¼ cup of batter into the skillet, swirling to coat the bottom evenly. Cook until the edges start to lift and the bottom is golden, about 1-2 minutes. Flip and cook for another 30 seconds. Repeat with remaining batter.
In a separate bowl, whip the heavy cream until stiff peaks form. Fold in the mascarpone cheese, powdered sugar, lemon juice, and lemon zest until smooth.
To assemble, place one crepe on a cake stand or plate. Spread a thin layer of lemon cream filling over the crepe, then sprinkle with blueberries. Repeat layers until all crepes are used, finishing with a layer of lemon cream and blueberries on top.
Chill the crepe cake in the refrigerator for at least 1 hour before serving.